Compressed air operated pump



Oct. 6, 1931. w. s. HuLsE QHPRESSED AIR OPERATED PUMP Filed Nov. 15, 1930 2 Sheets-Sheet l .ll/V

W. S. HULSE coMPREssED AIR OPERATED YUM? Filed Nov. 15 1930 2 Sheets-Sheet 2 lll FuZcz-w 717 [f1/9. Hulse Patented Oct. 6, 1931 siren stares rarer cFFIca HALTER S. HULSE, OF MERCHANTVILLE, NEW JERSEY GOMPRESSPEEDi .AR PEEAIED PUMP Application led November 15, 1930. Serial No. 495,973.v

it is approximately empty,v the valve controlling the. admission of pressure fluid to the cylinder for forcing the water therefrom when the cylinder is tull andV controlling the release of pressure iluid from the interior of the cylinder Ywhen the water has been dischargedr Jrrom the cylinder to the desired amount.

One orn the objects of the present invention is to provide means whereby the mechanism controlling the inlet of air to and the outlet of air rom'the cylinder may be separated from the pump cylinder itself so that a remote control'is provided and so that the controlling parte may be placed in a position where they are readily accessible for repair, lubrication or the like.

A further object is to provide a modified term of balance tube ot the character shown in my prior patent and to provide positive means for opening the valve permitting the inlet et compressed air tothe cylinder and closing the air exhaust valve, said positive means operating in connection with the balance tube.

A Jfurther obj ect is to provide means whereby air inthe balance tubev gradually lost by absorption in the water may be replaced or replenished.

A further object is to provide means whereby a weight and lever will act to positively operate the valves controlling the eX- haust of air from the pump cylinder and the inlet of compressed air thereto and to provide in connection. with this lever, means whereby the lever will be caused to quickly move 4from one of its positions to the other to cause a quick action of the valves.

Other'objects will appear in the course of the following description.

My invention is illustrated in the accompanying drawings, wherein Figure 1 is a diagrammatic elevation partly in section of a pumping apparatus constructed in accordance with mykinvention;

Figure 2 is a like viewto' Figure 1, but

showing a slightly diierent form of apparatus;

Figure 3 is an'enlarged longitudinal sectional view of the lever yfor operating the valves; 1

Figure l isa diagrammatic view of the lever showing'the forces applied thereto.

Referring to Figure l, .10 designates the pump cylinder which is submerged in the waterof the well WV. The lower end of this pump cylinder is provided with an inlet valve inder 10 and out through the top of the cylinder is a discharge pipe 12 having therein, above the'top of the cylinder 10 the check valve 13. This pipe 12 extends nearlyto the bottom of the cylinder 10. The check valve 13 may be located anywhere along the water discharge pipe 12.

Disposed remote from the cylinder 10 and at thesurface of the ground is a chamber 1a having therein either a piston 15 or a diaphragm7 the piston and diaphragm being considered as equivalent elements. This element 15 will be hereafter referred to as the piston, though the term is to be understood as including the diaphragm. The piston 15 is connected to a piston rod 16 passing through opposite ends oi the cylinder 111-. Extending upward from the top of the cylinder `1() is a pipe 17 which is connected to two branches, one an air supply branch 18 Connected to a source of compressed air, and the other branch being an air discharge pipe 19. In the branch 1 18 or air supply pipe there is disposed a valve 20`and in the air discharge pipe 19 there is disposed a valve 21. When one of these valves is closed, the other is opened and vice versa. These valves 2O and 21 may be of any suitable Cil 2 Lescure character and are merely shown diagrammatically in the drawings.

Engaged with the lower end of the rod 1G one arm of a lever Q2, the other arm of which carries a weight 23 tending to force the short arm of the lever up and thus opening the valve 21 and closing the valve 20.

The particular construction of the level` 22 will be hereafter stated.

Extending from the top of the cylinder is the pipe Q4 which opens into the chamber 14 below the piston 15. Extending from the upper end of the chamber lll above the piston is a pipe 25 which I shall hereafter call the balance pipe which extends downward through the top ofthe cylinder 1() and extends down nearly to the lower end of the water discharge outlet 12 and is there provided with a bell 2G open at its lower end. Preferably, and for the purpose of supplying air to the pipe in order to compensate for the absorption of air by the water within the lower end of this pipe, there is provided an air supply pipe 27 which connected to the air supply pipe 1S beyond the valve 2O and to the pipe 25 beyond its point of connection to the chamber 14. Disposed in this pipe 27 is a needle valve 2S permitting of a small leakage 0f air from the air supply pipe into the pipe 27 and so into the pipe 25. A manually operable valve capable of being turned on and olf might be used in place of the needL valve.

The lever 22 is preferably hollow and contains therein a volume of mercury or like material designated 29. The lever is tubular so that the mercury can run from one end of the lever to the other. IVhen that arm of the lever which is engaged by the rod 1G is depressed, the mercury will run to that end of the arm to partially counter-balance the weight Q3. I'Vhen on the other hand, the lever has shifted even slightly, from its horizontal position, the mercury will run to the extremity of the weighted end of the arm, thus assisting the weight This mercury, it will be understood, also tends to cause the quick mo vement of the lever from two positions. Preferably the weight 23 is shiftable along the arm anv desired distance fr m the fulcrum 22 or the lever.

rl`he operation of the construction illusrated in Figure 1 is as follow It is assumed that the cylinder 10 is submerged in water and that the cylinder is practically empty. In this position of the parte, the weight 23 will have lifted the piston 15 opening the valve 21 and closing the valve 20, cutting olii the compressed air ,supply and permitting` the discharge of air from within the cylinder 10. The water will now enter the pump cylinder through the check valve 11 and the air above the water will escape through the pipe 17, the connection 19 and the valux 21. As the water rises above the bell 2G, air in 26 will be compressed, the pressure being communicated through the pipe 25 to the upper side of the piston 15. When the water has risen to a predctern'iined extent, this pressure wili force the piston down against the action of the counter-weight 23, closing the valve 21 and opening the valve Q0. Compressed air will now enter the cylinder through the pipe 17, forcing the water out through the discharge line l2. Under these circumstances, additional pressure will be put on the air in the bell 26 and the pipe. 25, but the volume of the bell 26 is sufficiently large in proportion to the volume of the pipe 25 that the reduction of volume of the air in these parts does not cause the water to rise to a greater extent than some fraction of the height of the bell 2G. As the water level in the cylinder 10 recedes, the pressure on the opposite sides of the piston 15 will tend to equalize and as soon as the pressures on opposite sides have nearly equalized, the lever 22 with its weight will again lift the pis-A ton and again shift the valves.

This operation takes place alternately and continuously. In my prior patent, the water column in 'the balance tube was alternately lower and higher than the water in the cylinder 10. In the present invention, however, as shown in Figure 1, the water level remains near the lower end of the balance tube aml the pressure through the balance tube is nlreater than that 'from the top of the cylinder 10, the difference acting against the lever 22 and its weight 29.

As the air in the pipe 25 and bell 26 will gradually be lost by absorption in the water, I have provided the connection 27, as a means for replacing the air that is lost. The needle valve 28 (if one is used) may be set to permit a continuous slight leakage of air or it may Le opened occasionally, if a manually operable valve is used, as the operator may choose, in order to replace or replenish the air within he bell 28 and pipe 25.

In Figure 2, I have shown an arrangement which may bc used where there is a relatively short distance between the air valves and the pump and where the action ol the pump is slow enough so that high velocities in the air lines are not required. In this ligure, like numerals are used for like parts. In this ligure, the cylinder 10 is shown longer than the cylinder 10 in Figure 1, and is provided at lower end with a [lap valve 11 as heretofore described and with the outlet water discharge pipe 12 having therein the check valve 13. Associated with the cylinder l0 is the piston chamber lil having therein a piston 15 as heretofore described. This piston carries the piston rod 1G bearing against the one arm of a lever 22 fulcrumed at 22 and ha vin '1i' the counter-weight 23 and a portion of hq- 'd such as mercury 29.

In this rase, I do away with the use of the exhaust pipe controlled by the valve 21. The

` balance pipe 25 is connected directly to the valve20 and extends downward through the top of the cylinder 10 and has a relatively long bell 26 corresponding except in length With the bell 26. The pipe 24 is connected by a branch 24aL to the lower end of the chanr' ber 14 While the air supply pipe 25 is connected by a branch 25"t to the upper end ot the chamber 14. A needle valve 30 is disposed at the end of the air exhaust pipe 24 beyond the valve 21 and a vneedle valve 31 is disposed at the inlet end of the air supply 25 beyond the valve20. Y

The valves 3() and 31 may be needle valves or not as circumstances may dictate. These valves are placed at the exhaust and supply lines to regulate the flow of air so that there will beno changes 0I" pressures on the piston so abrupt as to interfere with the operation of themechanism.

The general action of the pump is the same as for the pump shown in Figure 1. The lever 22 With its Weight opens the exhaust valve 21 and. closes the air supply valve 20. As the air in the cylinder 10 escapes through the pipe 24, Water enters through the lap valve 11 andrising above the mouth of the bell 26'v1 compresses thefair in 26a and in the pipe 25. This pressure is communicated to the upper side of the piston 15, forcing the piston down against the action of the counter-Weight 23, closing the valve 21 and opening the valve 20. Compressed air Will now enter through valve 2() and pipe 25, rising through the Water from the bottom of the bell 2S to the top of the cylinder Where it builds up a pressure that forces Water out through the discharge pipe 12.

As the Water recedes, the pressures on opposite sides of the piston 15 tend to equalize and then the lever and Weight can operate the valves.

The lever 22 is preferably ot` iron, (if mercury is to be used) ,and inasmuch as the hollow interior of the lever 22 is partially filled with mercury, the mercury Will run from one end to the other With the movement ofthe lever. This mercury at first resists a move ment yof the lever and then when the lever is'moved beyond a horizontal position in either direction, gives an impulse to the movement of the lever and piston. This assures that a movementonce started Will, be

intended to cover anyother gas such as natural gas, air-inert gas,'etc.

It will be seen thatthere are two pressures acting on opposite sides of the piston 15,

one of these pressures, which is the pressure i on top of the liquid in cylinder 10 is transmitted to the lower side ofthe piston by the equalizer pipe 24 and its branch 24a. The other pressure, which is the vpressure on top of the liquid in the pump cylinder'lO, plus the pressure due to the height or" the Water in the pumpcylinder above the bottom ot' the balance pipe 25 and its bell 26, is trans mitted to the upper side of the piston by the balance pipe 52. The difference in these pressures, that is, the pressure acting on the under side of the piston and that acting on the upper side is .due to the height of Water in the pump cylinder above the bottom ot' the balance pipe or above the bottom of the '7 bell 26, Whether this pressure .on top of the Water is atmospheric'or a higher pressure as the pressure on .top of the ivater is balanced out by the equalizer pipe. As thisv force or pressure `P in thepipe25 varies with the height of Water in the pump cylinder, it is necessary to so design the lever'22 and its Weights' 23 and 29 that when theV pressure above the piston has reached corresponding value to the lieightto which We Wish the pumpcylinder to be iilled, it Will overbalance the `Weights 29 andv 23 to cause the valves to operate. l yThe moments due to the Weights on the'lever must' now be changed so that the lever yWill not overbalance the pressure or if forcefexerted on the top of the piston as this force decreases with the fall of the water jlevel in the pump :cylinder until the Water hasfallen a'desired amount. This is accomplished by .using the movable Weight, as forL maximum head against Which the pump is to operate'has no bearing on the design except in determining the size of the bell at the lower c end of the balance tube.

Tn Figure 4, it is shown that the. piston rod 16 impinges onthe lever 22 only ashortf distance, as for instance one inch from the tul crum. This is desirable because the stroke of the piston should be very short and the slope of the 'lever should be rather steep.

The short stroke ot the piston operating at a considerable distance from the fulcrum would not give'therequired slope to the lever, this slope being required in order that the mercury may move'rapidly from one end of the lever to the other.

The length of the i;

I o li )ne of the particular features of this pump is the use of the balance tube and the tube 25 connecting therewith and communicating with the cylimlei of the valve operating mechanism on one side of the piston (or diaphragm) and the tube 24 connecting with the upper portion of the pump cylinder and comnmnicating with the cylinder of the valve operating mechanism on the opposite side of the piston, by which arrangement of tubes, a difference in pressure, which is directly proportional to the height of water in the pump cylinder, is caused to act on the piston of the valve operating mechanism.

Another feature of the invention is in the use of the fixed weight 23 and the movable weight with the several parts so arranged that the pressure in the balance tube 25 and the upper portion of the pump cylinder being communicated to the opposite sides of the piston, the differences between these pressures will create a force tending to move the piston in one direction, which will be opposed by the action of the lever and weights tending to move the piston in the opposite direction, the movable weight, by being transferred from one end of the lever to the other with movements of the lever, giving two delinite values to the force exerted by the lever and fixing definite heights of water in the pump cylinder for which the difference in the pressures on the piston and the opposing action of the lever will cause the piston to move in one direction or the other, thus causing the simultaneous opening of one valve and the closing of the other valve in proper order for the operation of the pump.

The advantages claimed for this pump in addition to those common to all pumps of this general class, are that the shifting of the air inlet and exhaust valves is positively controlled by the level of the liquid in the pump cylinder to the same extent as in pumps in which the opera-tion of these valves is controlled by a float or floats in the pump cylinder with the elimination of the floats, rods, levers and packing sleeves that are required with floats and with generally less clearance in the pump cylinder than is possible where floats are used. Another advantage lies in the elimination of all moving parts in the pump cylinder itself with the exception of the tvo check valves, one of which is in the pump cylinder proper and the other of which in the discharge pipe l2. This permits the pump cylinder or tank to be built in a variety of shapes from a tank of very small diameter to be used in a driven well to a tank of large lateral dimensions to be used in a shallow sump, proper proportioning of the balance tube and piston of the valve operating mechanism causing the pump to operate with any particular rise and fall of 1. the water in the pump cylinder desired, from one of only a few inches to one of several feet.

Another advantage due to my construction is that the valve operating mechanism can be placed at a considerable distance from the pump cylinder securing a remote control and permitting it to be placed in an accessible location where the pump c Ylinder itself is in an inaccessible location as for instance when placed in a well.

Another advantage due to my construction is that the positive control of the air valves is negligibly affected by variations in the depth to which the pump cylinder is submerged or to variations in the head against which it is pumping. Furthermore, the positive control of the shifting of the air valves assures that the discharge stroke will not begin until the pump cylinder is completely filled with liquid and that the discharge stroke will end before air can pass through the pump and out through the water discharge pipe, thus making this pump especially desirable for pumping the maximum capacity of a low yield water or oil well, or for use as a sump pump as no energy is wasted, or consumed except when the pump actually puniping.

ln order to further explain the function of the lever 22 with its permanent weight 23 and movable weight 29, in regulating the stroke and point of cut-olf of the pump, attention is directed to the diagram in Figure 4.

Assume that the weight of piston and the piston rod is two pounds and the pressure P acting on the upper face of the piston is 26.5 pounds when the water is at a level X-X. The total force acting on the piston will then be 281/2 lbs. Assume that the fixed or permanent weight 23 is 1 lb. and the weight of the mercury 29 one lb. It is obvious that the length of the arm d must be 14.25 as shown by the following equation 28.5 lbs. X122 lbs. x 14.25.

This will bring the lever 22 to a horizontal position and at this time the mercury will flow to the other end of the lever, thus holding the lever with the weight raised. The

yweighted end of the lever must remain raised until the water in cylinder l0 has discharged. lf it were not for the mercury 29 or other shiftable weight, the permanently weighted end of the lever would lower `inst as soon as Y the pressure in the balance pipe 25 has decreased by the lowering of the water slightly below the point X-X, but as the mercury has shifted over to the opposite end of the lever from the permanent weight, it acts to counter-balance t-he weight until the water has been lowered to slightly below Y-Y, the points X-X and Y-Y being the levels of water in the pump at which the forces on the lever are inY equilibrium with' the mercury at opposite ends of the lever.

' When this happens, for instance, when the l lb'. X 14.25=7 lbs. x l inrtl lb. x d1 or In this equation, the weight of the lever, that is, the relative weights of the two arms of the lever have been disregarded, andas d has a length twice as-long as the armrl the fixed weight will have to be reduced to compensate for the excess weight of the lever arm d( Of course, the xed Weight 23 could be eliminated and thearm l be extended to form or constitute said fixed weight.` lt will, therefore, be seen that the movable weight not only constitutes a means whereby the action is rapid in shifting the piston but that it is a very kimportant Vfeature of the invention inasmuch as it prevents any movement koi the piston when the water is being discharged until the water has lowered to a definite point and prevents any movement of the piston when the water is entering the c vlinderand until the water has risen to a delinite point. Y

I claim l. In a pump of the character described, a tank having an inwardly opening check valve, a discharge pipe extending from the bottom of the tank, a pipe. leading'from a source of compressed fluid into the tankand having a valve, and an exhaust pipe leading from the tank and having a valve, means positively acting to urge the air supply valve to a closed position and the exhaust valve to an open position, and fluid pressure operated means acting against the force of said urging means, when the tank is filled toa predetermined degree, to shi it the air supply valve to an openfposition and the exhaust valve to a closed positionagainst the action of said urging` means, the means urging the air supply valve to a closed position and the exhaust valveV to an open position acting automatically when the liquid has allen'in the tanks to such a degree that the pressure oli' air is less than the force exerted by said urging means to open the air exhaust valve and close said air supply valve, the shifting of said valves resulting solely from changes in the magnitude of the force exerted by said fluid pressure operated means caused by the rise and fall of the liquid level in said tank.

2. In a pump ofthe character described, a tank having an inwardly openingl check valve, a discharge pipe extending from bottom ot the tank, a supply pipe leading from a source ofcompressed fluid into t-he tank and having valve, an exhaust pipe leading from the tank and having a valve, a chamber having piston operating therein and having positive connection to the 'two valves, the piston when moved in one direction acting to closethe supply valve', and open the exnaust valve, and when shifted in the other directien, simultaneously opening the supply v valve and closingthe exhaust valve, reguable means positively urging the piston in a direction to open the discharge valve and closel the supply valve, and means acting when the tank is Jfull toshift the piston to open the supply valve and close the exhaust valve Vagainst the action ot lsaid urging means and 'terminating at a Apoint above the vdisf charge pipe, and an equalizing pipe connectedto the opposite end of said chamber and extending into the tank.

3. In a pump of the character described, a tank having an inwardly opening check valve, a discharge pipe extending from bottom et the tank, la supply pipe leading from a source ci compressed fluid into the tank and having a valve, an exhaust pipe leading from the tank and having a valve, a chamber having a piston operating therein and having a positive connection to the two valves, the piston when moved in one direction acting to close the supply valve, and open the' exhaust valve and when shifted in the other direction simultaneously opening the supply valve and closingV the exhaust valve, regulatable means positively urging the piston in a direction to open the discharge valve and close the supply valve, and means acting when the tank is full to shift the' pisten te open the supply valve-and close the exhaust `valve against the action of said urg ing means and including a tube connected to that endfof said chamber opposite the urging means, said tube extending downward inte the tank and terminating in a downwardly opening bell larger in rdiameter than the tube, there lbeing means for nearly equalizing the fluid pressure on opposite sides of the piston when the liquid in the tank has descended to a' predetermined degree to thereby permit the regulatable means to act.

4. InV a pump ofL the character described, a tank 'having an inwardly opening check valve, a discharge pipe extending from the bottom of the tank and having a check valve, a pipe leading from `a' source of compressed fluid inte the tank and having a valve, an exhaust pipe leading from the'tank and having a valve, means positively acting toY urge the first named valve to a closed position and the exhaust valve Vte an open position, a valve operating element common to both of said valves and including a chamber and a piston therein, pressure means acting as the liquid rises in the tank to compress fluid on the side of said piston opposite the urging means until the pressure counterbalances the urging means to thus cause the closure of the exhaust valve and the opening of the compressed fluid inlet valve, and means for cause ing approximate balancing ot' pressures on opposite sides of the piston when the liquid has lowered in the tank to a predetermined degree to thus permit the urging means to close the compressed fluid inlet valve and open the exhaust valve.

5. In a pump of the character described, a tank having an inwardly opening cheek valve, intake and exhaust ports, said tank being adapted to be submerged, a discharge for said tank having an outwardly opening check valve, controlling means shiftable upon unbalancing of the pressure at opposite ends thereof for cont-rolling' the inlet and exhaust ports, a source of .fluid pressure supply in communication with the intake port and an adjustable weight urging the controlling means to a position where the inlet of compressed fluid is cnt ofi1 and exhaust permitted, and means whereby the ingress of liquid to said tank to a predetermined degree counteracts said weight to thereby cause the opening of the exhaust valve and the closing of the compressed fluid inlet valve whereby when liquid has been discharged `from the tank to a predetermined degree, the pressures on the opposite sides oll the controlling means will be nearly balanced to thus permit the weight to close the compressed air supply valve and open the exhaust valve.

6. In a pump of the character desinibed, a tank having an inlet valve, a discharge pipe leading from the tank, a chamber having therein a piston, a piston rod extending through the chamber, a compressed fluid supply pipe having a valve, an exhaust pipe having a valve, both of said pipes being connected to the tank, the valves being conne, zd to the piston rod for sin'iultaneous operation in relatively reverse directions, a lever engaged with the piston rod and carrying a weight urging the piston rod in a direction to close the supply valve and open the exhaust valve, means i'or transmitting a greater fluid pressure to the interior of the chfnnbei` on th at side ot the piston opposite the lever than, is transmitted to the other side ot' the pistonv to thereby counter-balance said weight and open the supply valve while closing the exhaust valve when the tank is filled to a predetermined degree and reducing the fluid pressure against said faceot the piston relative to the fluid pressure on the opposite Jface when the tank has emptied to a predetermined degree to thereby permit the weight to close the supply valve and open the exhaust valve.

7. In a pump of the character described, a tank having an inlet valve,v a. discharge pipe leading from the tank, a chamberhavin g therein a piston, a piston rod extending through the chamber, a compressed 'luid supply pipe having a valve, an exhaust pipe having a valve, both ot' said pipes being connected to the tank, the valves being connected to the piston rod for simultaneous operation in relatively reverse directions, a lever engaged with the piston rod and carrying a weight urging the piston rod, in a direction to close the supply valve and open the exhaust valve, means for transmitting iuid pressure 'from within the tank to both sides of the piston, said means causing a greater pressure upon that side of the piston opposite the lever than to the other side 0i the piston when the tank is filled to a predetermined degree to thus counter-balance said weight and open Jthe supply valve while closing the exhaust valve.

8. In a pump of the character described, a tank having an inlet valve, a discharge pipe leading from the tank, a chamber having therein a piston, a piston rod extending through the chamber, a compressed fiuid supply pipe having a valve, an exhaust pipe heving a valve, both of said pipes being connected to the tank, the valves being connected to the piston rod 'for simultaneous operation in relatively reverse directions, a lever engaged with the piston rod and carry ing a Weight urging the piston rod in a direction to close the supply valve and open the exhaust valve, means for transmitting fluid pressure from within the tank to both sides of the piston, said means causing a greater pressure upon that side of the piston oppov site the lever than to the other side of the piston when the tank is filled to a prcdetei-mined degree to thus countcr-lnilance said weight and open the supply valve while closing the exhaust valve, and comprising a ha ance pipe extending from that end of the chamber opposite the lever down into the tank to a point acentto or above the lower end oli the discharge pipe and an equalizer pipe extending from the top o't the faul; into the opposite end of the chamber.

9. In a pump ot the character described, a tank having an inlet Valve, a d-fhargc valve leading from the tank, a chamber hrzving therein a piston, a piston rod extending tlnongh the chamber, a compressed fluid supply pipe having a valve, an exhaust pine hav ing a valve, both of said 'pcs being ecnnected to the tank, the valves being conI nected to the piston rod for simullaucmis operation in relatively reverse directionsA a lever engaged with the piston rod and earrying a weight urging the piston rod in a direction to close the supply valve and open the exhaust valve, a balance pipe extending from that end of the chamber opposite the lll lever dov-:n into the tank to a point adjacent to but above the lower end ot' the discharge pipe and having a downwardly opening bell larger in diameter than the balance pipe and an equalizer pipe extending from the tank and opening into that end of the chamber adjacent the lever.

l0. In a pump of the character described, a tank having an inlet valve, a discharge valve leading from the tank, a chamber having therein a piston, a piston rod extending through the chamber, a compressed fluid supply pipe having a valve, an exhaust pipe hai-zing a valve, both of said pipes being con-k nected to the tank, thevalves being connected to the piston rod for simultaneous operation in relatively reverse directions, a lever engaged with the piston Vand carrying a weight urging the piston rod in a direction to close the supply valve and open the exhaust valve, a balance pipe extending from that end of the chamber opposite the lever down into the tank to a point adjacent to but above the lower end or the discharge pipe and having a downwardly opening bell larger in diameter than the balance pipe and an equalizer pipe extending from the tank and opening into that end ot' the chamber adjacent the lever, the lever having a movable weight shitable as the lever is tilted from a horizontal position from one end et the lever to the other.

l1. In a pump of the character described, a tank having adischarge pipe, a compressed fluid supply pipe having a valve, an exhaust pipe having a valve, both or' said pipes being connected to the tank, a piston, a piston rod extending through the chamber, the valves being connected to the piston rod for simultaneous operation in relatively reverse directions, a chamber having therein a piston carrying said rod, a balance pipe extending down into the tank to a point adjacent to but above the lower end ot the supply pipe, and connected to said chamber on one side ot the piston, an equalizer pipe connected to the chamber on the opposite side of the piston, and means whereby absorption of compressed fluid in the balance pipe may be compensated for.

l2. n a pump of the character described,V

to operate them in relatively reverse direc-y tions, .means urging the piston rod in a direction to close the supply valve and open the exhaust valve, a connection from the air supply pipe between its valve and the tank to thatl end of the chamber opposite the urging means, and a connectionifrom the exhaust pipe to the opposite end of the chamber.

13. In a pump of the character described, a tank having'an inlet valve and a discharge pipe, a chamber having therein a piston, a piston rod extending through the chamber, a compressed luid supply pipe having a valve and extending down into the tank and terminating in a downwardly opening bell adjacent to but above the lower end of the discharge pipe, an exhaust pipe leading from the upper end of the tank and having a valve, said piston rod being connected to the valves to operate them in relatively reverse directions, speed reducing valves on the inlet side of the supply pipe and outlet side of the exhaust pipe, means urging the piston rod in a direction to close the supply valve and open the exhaust valve, a connection from the air supply pipe between its valve and the tank to that end of the chamber opposite to the urging means, and a connection from the exhaust pipe to the opposite end of the chamber.

lll. Inv a mechanism of the character described, a compressed fluid supply pipe and an exhaust pipe, valves for said pipes, pressure operated means for reversely operating said valves, means for urging said pressure operated means in a direction to close the Huid supply valve and open the exhaust valve comprising a lever tiltable in a vertical plane, and having an arm operatively engaging said means, and an arm carrying an adjustable counter-weight, the lever including a tubular element extending longitudinally thereof and having therein material freely movable as the lever is tilted from one end to the other of the tubular element whereby to retard the movement of the lever toward the horizontal position and accelerate the movement of the lever after it has passed its horizontal position.

15. In a mechanism of the character described, a tank having an inlet valve and a discharge pipe extending from near the bottom of the tank, a chamber having therein a piston and a piston rod, a balance pipe extending from a point within the tank above the lower end of the discharge pipe and communicatmg with the interior of said cham-- ber on one side of the piston, an equalizer pipe communicating ybetween the other side of the chamber and the top of the tank, means for introducing compressed air into the in- 1 terior of the chamber at the top thereof or exhausting air therefrom,- and including reversely operated valves, a piston rod being operatively connected to said valves to reversely operate them when the piston isv` moved from a normal position in either direction, a lever pivoted intermediate its ends and having one arm engaged with the piston rod, a permanent weight urging the other bai :l r1n downward to thereby shift the piston rod to fr position to close the compresed air supply Vvalve and open the exhaust valve, the lever having :L movable weight vslnftahle from 5 one end of the lever to the other.

In testimony whereof I hereunto affix my signature.

TALTER S. HULSE. 

